Confidence
Fair - Due to limited field observationsfor the entire period
Weather Forecast
The current weather pattern is expected to hold Thursday and Friday with a temperature inversion bringing above freezing temperatures to alpine elevations. The associated valley cloud is expected to blow out Wednesday afternoon with moderate northerly outflow winds, resulting in sunny skies at all elevations. A week frontal system is expected for Saturday with increasing cloud and a chance of light precipitation and moderate westerly winds.
Avalanche Summary
One very recent size 2 slab was observed on Sunday on a north facing slope close to Keith's Hut in the Duffey Lake area. It appeared to be skier-triggered from the weekend.
Snowpack Summary
Surface hoar continues to grow and is getting really big on shady slopes below treeline, but steep sun-exposed slopes are pretty crusty. The thick rain crust from last weekend extends up to 1800m and is buried by 10-15cm of faceted snow. Total treeline snowpack depth is 150-180cm but wind-exposed areas are highly variable with scoured areas and deep 3+ metre drifts. Recent observations from wind scoured alpine slope in the Duffey Lake area include inconsistent hard sudden compression test results down 70cm on buried surface hoar, and just off the ground in facets. On a more sheltered westerly aspect moderate to hard sudden shears were observed down 40-50cm and 70cm on rounding facets.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.